1. Field of the Invention
The present invention relates to a robot cleaner, and more particularly to, a system for automatically exchanging cleaning tools of a robot cleaner which can automatically exchange the cleaning tools of the robot cleaner, and a method therefor.
2. Description of the Background Art
In general, a robot cleaner is an apparatus for automatically cleaning a specific area by running in a house (for example, a living room, a main room, etc.) and sucking foreign substances such as dust from the bottom without operations of the user.
The robot cleaner runs in a preset cleaning path and performs a cleaning operation according to a built-in program. A plurality of sensors are used to sense a position of the robot cleaner, a running distance of the robot cleaner and obstacles near the robot cleaner, so that the robot cleaner can automatically run in the preset path and perform the cleaning operation.
However, because the high-priced sensors are installed in the robot cleaner so that the robot cleaner can precisely run in the preset path and perform the cleaning operation, the inside structure of the robot cleaner is complicated and the prime cost of production is increased.
In order to solve the above problem, there has been suggested a robot cleaner which randomly runs in a predetermined cleaning path and performs a cleaning operation.
FIG. 1 is a block diagram illustrating a running device of a conventional robot cleaner.
Referring to FIG. 1, the running device of the conventional robot cleaner includes an obstacle sensing unit 1 for sensing an obstacle when the robot cleaner goes straight in a predetermined area and runs against the obstacle, a control unit 2 for sopping running of the robot cleaner according to the output signal from the obstacle sensing unit 1, generating a random angle according to a random method, and rotating the robot cleaner by applying the random angle as a rotary angle of the robot cleaner, a left wheel motor driving unit 3 for driving a left wheel motor 5 of the robot cleaner at a predetermined speed according to the control signal from the control unit 2, and a right wheel motor driving unit 4 for driving a right wheel motor 6 of the robot cleaner at a predetermined speed according to the control signal from the control unit 2.
The operation of the conventional robot cleaner will now be explained with reference to FIG. 2.
As illustrated in FIG. 2, the running method for the conventional robot cleaner includes the steps of, when a cleaning command is inputted by the user, making the robot cleaner go straight and sensing an obstacle (S1 to S3), when the obstacle is sensed, stopping the robot cleaner and generating a random angle according to a random method (S4), applying the random angle as a rotary angle of the robot cleaner and rotating the robot cleaner by the rotary angle (S5), making the rotated robot cleaner go straight (S6), and deciding completion of the cleaning operation of the robot cleaner while the robot cleaner goes straight and stopping running of the robot cleaner when the robot cleaner completes the cleaning operation.
The running method for the conventional robot cleaner will now be described in more detail.
When the cleaning command for the robot cleaner is inputted by the user (S1), the control unit 2 outputs the control signal for equalizing a driving speed of the left wheel motor 5 with a driving speed of the right wheel motor 6, so that the robot cleaner can go straight.
The left wheel motor driving unit 3 drives the left wheel motor 5 according to the control signal, and the right wheel motor driving unit 4 drives the right wheel motor 6 according to the control signal. Therefore, the robot cleaner goes straight by the left wheel motor 5 and the right wheel motor 6 (S2).
While the robot cleaner goes straight, if the robot cleaner runs against an obstacle, the obstacle sensing unit 1 senses the obstacle by an impact, and transmits an obstacle sensing signal to the control unit 2 (S3).
Accordingly, the control unit 2 stops running of the robot cleaner according to the obstacle sensing signal, generates the random angle according to the random method (S4), and outputs the control signal for applying the random angle as the rotary angle of the robot cleaner. Here, the control unit 2 outputs the control signals for making the speed of the left wheel motor 5 different from the speed of the right wheel motor 6 to the left wheel motor driving unit 3 and the right wheel motor driving unit 4, so that the robot cleaner can be rotated by the rotary angle.
The left wheel motor driving unit 3 drives the left wheel motor 5 according to the control signal from the control unit 2, and the right wheel motor driving unit 4 drives the right wheel motor 6 according to the control signal from the control unit 2. As a result, the robot cleaner is rotated by the random angle (S5).
Thereafter, the control unit 2 outputs the control signals for equalizing the speed of the left wheel motor 5 with the speed of the right wheel motor 6 to the left wheel motor driving unit 3 and the right wheel motor driving unit 4. Thus, the robot cleaner goes straight (S6).
While the robot cleaner goes straight, completion of the cleaning operation of the robot cleaner is decided. When the cleaning operation is completed, running of the robot cleaner is stopped and the cleaning operation is ended. When the cleaning operation of the robot cleaner is not completed, the routine goes back to the step for sensing the obstacle, to repeat the above procedure.
However, the conventional robot cleaner has a disadvantage in that the user must examine the bottom state of the cleaning area of the robot cleaner and exchange the current cleaning tool with the cleaning tool suitable for the bottom state. Accordingly, the conventional robot cleaner reduces conveniences of the user. Moreover, when the user mistakenly recognizes the bottom state of the cleaning area, the conventional robot cleaner cannot efficiently clean the cleaning area.